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If your boiler has stopped working in a cold snap, check whether its condensate pipe has frozen before you call out a heating engineer.

When cold weather sets in, one of the most commonly reported faults is that a boiler's condensate pipe has frozen.

This fault will cause your boiler to shut down – but it's the boiler's way of keeping you safe, if not warm. 

If this pipe gets blocked with ice, or anything else, then your boiler will automatically shut down as a safety measure.

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Prevention is always better than a cure,  and with the UK weather becoming more 'extreme' due to the effects of global climate change, we may see prolonged periods of sub-zero temperatures .

Follow our tips to stop your pipes from freezing in the first place.

If possible, the condensate pipe should run internally as far as possible. The less pipe that sits outside, the better. 

You won't be able to change yours yourself; you'll need to pay for a heating engineer to complete the work. But if your condensate pipe is known to freeze over, it will be time and money well spent getting a solution put in place.

When you next get your boiler serviced, ask the engineer if any improvements can be made. They will be able to tell you if your condensate pipe can be run internally. 

If the pipe cannot be connected internally, the next thing to consider is insulating any sections of the condensate pipe that run externally. 

This is especially important if it's high up and therefore difficult to unfreeze using hot water. 

You can insulate a pipe yourself, but unless you absolutely know what you're doing you should call in a professional for an assessment.

This will ensure the correct material is used for the insulation (it should have a waterproof and UV-resistant coating) and be installed to the latest regulations according to BS 6798:2014.

Which? Trusted Traders  – find a plumber, heating engineer or handyman in your area

Make the condensate waste pipe as large as possible. Check your manufacturer’s instructions – some will recommend that it should be at least 32mm or up to 40mm. 

The internal diameter shouldn't be smaller than 30mm.

Get your heating engineer to inspect the condensate pipe and install a wider pipe, should that be necessary. 

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If you've already implemented the tips above but your external condensate pipe still freezes over, here are some more changes that could help. 

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If your boiler is consistently developing costly faults, it could be time for a new one. 

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